根據崩潰理論研究擷取振動能之壓電發電機

Abstract

近年來社會大眾都在關注能源問題，因而再生能源議題被世人所關切。本研究是利用壓電材料的性質，設計一個小型發電裝置擷取環境周遭的機械能，並轉換成電能。研究使用陶瓷雙晶片壓電片，利用壓電片彎曲方式來發電，並運用能量法及漢彌爾頓定理來推導計算壓電片的自然頻率，有限單元分析軟體ANSYS模態分析，得到壓電片的振動模態和自然頻率，比較理論計算獲得的自然頻率結果一致。本研究的發電機構使用線性彈簧與壓電片作結合，並運用崩潰理論進行設計，使線性彈簧在壓縮過程中產生挫曲的非線性振動，以及彈簧容易受激振特性，以提高壓電片振動幅度，增加發電量。將發電裝置基座連接線性馬達來模擬振動環境，再利用數位電表測量其發電電壓和電流，並且比較崩潰與無崩潰現象的發電量，發現無崩潰現象量測得到電壓為0.702V、電流為"5.02×" 〖"10" 〗^"-7" A，有崩潰現象量測得到電壓為1.28V、電流為"8.96×" 〖"10" 〗^"-7" A，電壓與電流都有明顯的增加。最後將兩個並聯的壓電片進行電路整流後，量測得到最大的瞬間電壓為2.42V、電流為"2.29×" 〖"10" 〗^"-6" A。

Recently, the public are concerned about energy issues, thus the issue of the renewable energy have drawn attention. Due to the properties of piezoelectric materials, we can design a small generator to collect mechanical energy from environment, and then transform it into electrical energy. The piezoelectric bender used in this study is bimorph. The generator uses bending piezoelectric elements to generate electricity. This study uses an energy method and Hamilton’s principle to calculate the vibrational natural frequencies of piezoelectric benders. The finite element analysis software ANSYS is carried out to obtain vibration modes of piezoelectric benders and natural frequencies, which are consistent with theoretical calculation of the natural frequencies. In this study, the power generation mechanism contains to linear springs attached to piezoelectric benders. Based on a catastrophe theory, this study makes linear springs produce buckling nonlinear vibration during compression. The linear springs which are susceptible to excitation of characteristics increase the vibration amplitude of the piezoelectric benders, so as to enhance electrical energy. The foundation of power generating device is connected to a linear motor to simulate vibrational environment. A digital multimeter is thus employed to measure the voltage and current. Comparing power generation of the mechanism with catastrophe phenomenon and without catastrophe phenomenon shows that the latter is measured at 0.702V and "5.02×" 〖"10" 〗^"-7" A and the former is measured at 1.28V and "8.96×" 〖"10" 〗^"-7" A. The results of voltage and current have increased significantly due to the catastrophic situation. At last, dealing with two benders in parallel, the maximum instantaneous voltage 2.42V and current "2.29×" 〖"10" 〗^"-6" A are measured after the rectifier circuit.